Loximuthal Projection
Nov 5,2025

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Introduction

Loximuthal projection is a pseudocylindrical map projection proposed by Carl Simon in 1935. Its core characteristic is that rhumb lines (loxagonal courses) from a central point (the intersection of the central meridian and the central parallel) are displayed as straight lines, while maintaining true bearing and scale. The projection is neither equal-area nor conformal, but was originally designed to provide accurate compass bearings for maritime navigation while clearly defining local shapes by accurately representing course and distance from a central point.

Projection Basic

Rhumb Line Straightening: All rhumb lines (i.e., compass bearings) originating from the center point are rendered as straight lines, a characteristic that provides a unique advantage in nautical navigation.

Azimuth and Scale Trueness: Azimuths and scale radiating outward from the center point remain true, but the overall projection does not maintain constant area or angles.

Local Shape Sharpness: The projection accurately and clearly defines local shapes near the center point, minimizing the effects of distortion on navigation.

Pros

High fidelity in mid-latitude regions: Minimal distortion in shape, area, and scale near standard parallels (e.g., 45°N/S), making it ideal for displaying geographic information in mid-latitude areas (e.g., Europe, North America, China).
Balanced global distortion: Compared to other cylindrical projections (e.g., Mercator), it offers milder stretching at the poles and compression at the equator, resulting in more visually proportional global maps.
Intuitive and easy to read: Straight, perpendicular meridians and parallels align with human perception, facilitating direction judgment and distance estimation.
Historical and practical value: Widely used in British atlases, it remains suitable for educational purposes, world maps, and general reference applications.

Cons

Significant distortion at high latitudes: Severe shape and area distortion near the poles (e.g., Greenland appears overly large), limiting its use for polar research or high-latitude navigation.
Neither equal-area nor conformal: Fails to preserve both area and angle simultaneously, restricting its utility in precise measurements (e.g., land planning) or navigation (e.g., maritime charts).
Limited versatility: Less adaptable than specialized projections (e.g., Lambert Conformal Conic for aviation, Albers Equal-Area for statistics) for targeted applications.
Competition from modern alternatives: The rise of digital mapping and dynamic projections (e.g., adaptive Mercator) partially addresses its fixed-perspective limitations.

Application Scenario

The Loximuthal Projection is suitable for scenarios that need to accurately present the course and distance from a specific point as the center, such as marine/aviation navigation, regional route planning, and radial transportation/communication network display.